JP2005114903A - Optical writing system and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical writing system which can suppress extention of noise and occurrence of rippling caused by heat, and to provide an image forming apparatus. <P>SOLUTION: The optical writing system has a polygon mirror 11 for deflecting and scanning irradiation light irradiated from a light source through an optical system, and an almost sealed room 14 in which the polygon mirror 11 is arranged, and the sealed room 14 is formed of a housing 12 which is partly open and a cover member 13 which covers the open part of the housing 12, and the cover member 13 is held so as to be slidable in the direction parallel to the mounting surface onto the housing 12. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical writing apparatus and an image forming apparatus.

JP 2001-337290 A

  Patent Document 1 describes an optical writing device used in a laser printer, a digital copying machine, a digital fax machine, or a combination of these, and a type in which a bearing is directly installed on a drive substrate and a polygon mirror rotates in a bare state. As described above, there is a type in which a polygon mirror is installed in a substantially hermetically sealed rotating space and rotates in a generally sealed state. Most of the polygon mirrors that rotate in a bare state are those that rotate at a relatively low speed, and many of recent image forming apparatuses rotate the polygon mirror at a high speed. Rotating under conditions.

  FIG. 6 is a cross-sectional explanatory view showing a conventional sealed optical writing apparatus. In FIG. 6, the polygon mirror 51 is disposed in a sealed chamber 54 as a substantially sealed rotating space formed by a housing 52 and a cover member 53. By arranging the polygon mirror 51 in the sealed chamber 54 in this way, wind noise generated by the rotation of the polygon mirror 51 can be suppressed to a low level.

  By the way, the sealed chamber 54 is configured so as to be covered with a cover member 53 on a partially opened housing 52 to facilitate assembly and maintenance. In this case, the cover member 53 has a planar shape and is fixed to the housing 52 by bonding and screw fastening. In the optical writing apparatus configured as described above, when the temperature of the writing apparatus rises as the polygon mirror 51 rotates, the shapes of the housing 52 and the cover member 53 change due to thermal expansion. At this time, the housing 52 and the cover member 53 differ in how they change due to differences in configuration and the like, and distortion occurs at the fixed portion. When distortion occurs, vibration occurs and noise increases. Further, when a gap is generated on the mounting surface due to the distortion of the fixed portion, a wind noise generated at the corner of the polygon mirror 11 leaks from the gap and noise increases.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical writing apparatus and an image forming apparatus that can eliminate the above-described conventional problems and suppress the expansion of noise and vibration caused by heat.

  In order to achieve the first object, the present invention includes a polygon mirror that deflects and scans the irradiation light emitted from the light source through the optical system, and a substantially sealed rotating space in which the polygon mirror is disposed, In the optical writing device in which the rotating space is formed by a housing that is partially opened and a cover member that covers the opened portion of the housing, the cover member slides in a direction parallel to a mounting surface to the housing It is characterized by being held possible.

The present invention is effective when the cover member is pressed and held by the elastic member in a direction in close contact with the housing.
Furthermore, the present invention is effective when the cover member is pressed substantially at the center of the mounting surface by the elastic member.

  In order to achieve the above object, the present invention includes the optical writing device according to any one of claims 1 to 3, and the optical writing device performs writing on the photosensitive member by light. It is a feature.

  According to the configuration of the first aspect, since the cover member is slidably held in the direction parallel to the mounting surface to the housing, it is assumed that there is a difference in the shape change between the housing and the cover member due to the temperature rise. In addition, the cover member 13 can slide in a direction parallel to the mounting surface to prevent the occurrence of distortion or the like.

  According to the configuration of claim 2, since the cover member is pressed and held in the direction of being in close contact with the housing by the elastic member, the pressing force of the elastic member in the direction perpendicular to the mounting surface does not change even when the temperature rises. The cover member is brought into close contact with the mounting surface of the housing to prevent a gap from being formed between the housing and the cover member, and leakage of wind noise from the gap can also be prevented.

  According to the configuration of the third aspect, since the cover member is pressed substantially at the center of the mounting surface by the elastic member, the close contact force of the cover member to the housing is uniform over the entire region, and the cover member is displaced due to uneven contact force. And the occurrence of gaps can be prevented.

  According to the configuration of the fourth aspect, it is possible to provide an image forming apparatus that can obtain the above-described effect.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is an explanatory view showing an outline of a laser printer as an image forming apparatus according to the present invention. It has a laser writing device for writing. First, an outline of the image forming means will be described.

  The image forming means in FIG. 1 has a drum-shaped photoconductor 1, and the photoconductor 1 is driven to rotate clockwise in FIG. 1, and at this time, the surface is uniformly charged to a predetermined polarity by a charging roller 2. Then, the charged surface is irradiated with a light-modulated laser beam L emitted from a laser writing apparatus 10 described in detail later. As a result, an electrostatic latent image is formed on the photosensitive member 1, and the electrostatic latent image is visualized as a toner image by the developing device 3.

  On the other hand, a recording material P made of, for example, transfer paper is fed from a paper feeding device 7 provided on the lower side of the apparatus main body, and the recording material P is interposed between the photoreceptor 1 and the transfer roller 4 via a registration roller 8. It is sent. A voltage having a polarity opposite to that of the toner on the photoreceptor 1 is applied to the transfer roller 4, whereby the toner image on the photoreceptor 1 is transferred onto the recording material P. The transfer residual toner that is not transferred to the recording material P and remains on the photosensitive member 1 is removed by the cleaning device 5, and further, the residual charge remaining on the photosensitive member 1 is removed by the charge eliminating device 6.

  The recording material P on which the toner image is formed in this manner is sent to the fixing device 9 via the conveying belt 25. At this time, the toner image is fixed on the recording material P, and the recording material P after the fixing is finished. The paper is discharged onto the paper discharge tray 26. As described above, the image forming apparatus illustrated in FIG. 1 includes the image forming unit and the optical writing device 10 that performs optical writing with the laser beam on the photosensitive member 1 of the image forming unit.

  FIG. 2 is an enlarged explanatory view of the main part of the optical writing device 10. The optical writing device 10 shown here is a substantially sealed type, and the polygon mirror 11 is substantially sealed formed by a housing 12 and a cover member 13. It arrange | positions in the sealed chamber 14 as a rotation space. By arranging the polygon mirror 11 in the sealed chamber 14 sealed by the cover member 13, the sound generated by the rotation of the polygon mirror 11 can be reduced. The sealed chamber 14 is provided with an opening 15 that allows the laser beam to enter and exit the polygon mirror 11, and the opening 15 is closed by a soundproof glass 16.

  By the way, although the polygon mirror 11 is not shown in FIG. 2, a drive motor disposed below the polygon mirror 11 rotates around a rotation shaft 11a controlled by a drive control means disposed below. Due to this rotation, it is inevitable that the drive motor and the control means generate heat, and the sealed chamber 14 is exposed to a high temperature. For this reason, conventionally, distortion occurs in the mounting portion of the housing 12 and the cover member 13 due to thermal expansion and temperature distribution, and noise leakage and vibration may occur.

  Therefore, in the present embodiment, as shown in FIG. 3, a long hole 17 is formed in the cover member 13, and a head screw 18 screwed into the housing 12 is fitted into the long hole 17 so that the cover member 13 is It is attached. In fastening the head screw 18, a washer 19 and a coil spring 20 as an elastic member are interposed, and the cover member 13 is pressed against the housing 12 against the pressing force of the coil spring 20. That is, as shown in FIG. 2, the coil spring 20 is loosely fitted between the head of the headed screw 18 and the washer 19, and the screw 18 is fixed to the housing 12, whereby the cover member 13 is elastic of the coil spring 20. It is fixed to the housing 12 by force.

  Thus, since the cover member 13 is pressed and attached to the housing 12 through the long hole 17, the cover member 13 can slide parallel to the attachment surface of the housing 12. Therefore, even if a distortion occurs in the attachment portion of the housing 12 and the cover member 13 due to a difference in thermal expansion and temperature distribution, the cover member 13 slides, so that the generation of the distortion is prevented. The extending direction of the long hole 17 is set to the center point of the cover member 13, that is, the radial direction of the rotation axis of the polygon mirror 11, so that the cover member 13 slides and generates distortion even if thermal expansion occurs. It can be suppressed.

  In the above optical writing device, the pressing force of the coil spring 20 in the direction perpendicular to the mounting surface (up and down direction in FIG. 2) does not change even when the temperature rises, so that even if the cover member 13 slides so as not to cause distortion. It can be brought into close contact with the mounting surface of the housing 12. Therefore, there is no gap between the housing 12 and the cover member 13, and leakage of wind noise due to the occurrence of the gap can be prevented.

4 and 5 are explanatory views of a plane and a front showing another embodiment of the present invention.
4 and 5, the cover member 13 is pressed and fixed to the housing 12 by a leaf spring 21 as an elastic member. That is, the cover member 13 is brought into close contact with the housing 12 by the leaf spring 21, and the leaf spring 21 is fixed to the frame of the writing device by the screws 22 at both ends thereof. In this case, since the cover member 13 is not fixed to the housing 12 by fastening or bonding of screws, the cover member 13 can slide with respect to the mounting surface. Further, as is apparent from FIG. 5, the leaf spring 21 presses substantially the center of the cover member 13, so that the adhesion force of the cover member 13 to the housing 12 is uniform over the entire area, and the cover member 13 is not uniform due to the uneven adhesion force. Deviations and gaps can be prevented.

  The optical writing device configured as described above is attached to the housing 12 by pressing the leaf spring 21 even if a difference in shape change between the housing 12 and the cover member 13 occurs due to temperature rise. It is slidable in the direction parallel to the surface and no distortion occurs. For this reason, it is possible to provide an optical writing apparatus that does not increase vibration and noise due to distortion at the time of temperature rise, which has been a problem in the past.

  In the above optical writing device, the pressing force of the leaf spring 21 in the direction perpendicular to the mounting surface (up and down direction in FIG. 4) does not change even when the temperature rises, so that even if the cover member 13 slides so as not to be distorted. It can be brought into close contact with the mounting surface of the housing 12. Therefore, there is no gap between the housing 12 and the cover member 13, and leakage of wind noise due to the occurrence of the gap can be prevented.

1 is an explanatory diagram showing an outline of a laser printer as an image forming apparatus according to the present invention. It is a schematic sectional drawing which shows one Embodiment of the optical writing apparatus which concerns on this invention. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. It is a schematic sectional drawing which shows other embodiment of the optical writing apparatus which concerns on this invention. FIG. 5 is a plan view of FIG. 4. It is a schematic sectional drawing which shows the conventional optical writing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical writing apparatus 11 Polygon mirror 12 Optical housing 13 Cover member 14 Sealed chamber 20 Coil spring 21 Leaf spring

Claims (4)

A polygon mirror that deflects and scans the irradiation light emitted from the light source through the optical system, a substantially hermetically sealed rotating space in which the polygon mirror is arranged, a housing in which the rotating space is partially opened, and the housing In the optical writing device formed by the cover member covering the opened part,
The optical writing apparatus, wherein the cover member is slidably held in a direction parallel to a mounting surface to the housing. The optical writing apparatus according to claim 1, wherein the cover member is pressed and held by an elastic member in a direction in close contact with the housing. The optical writing apparatus according to claim 1, wherein the cover member is pressed substantially at the center of a mounting surface by the elastic member. An image forming apparatus comprising the optical writing device according to claim 1, wherein the optical writing device performs writing on the photosensitive member with light.

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